Wells, particularly oil wells, which penetrate subterranean formations in which the natural formation pressure is depleted to the level that the oil will not flow to the surface require that the oil be lifted to the surface by various means including pumping the oil from the producing formation to surface facilities.
One of the several available pumping units for raising and lowering a pump rod to drive a downhole pump includes a hydraulic fluid operated cylinder attached to the pump rod to raise and lower the rod to operate the pump. One particular hydraulic system utilizing a cylinder for driving the pump rod is the Tieben Pumping Unit manufactured and sold by Tieben Inc. West McArtor Road, Dodge City, Kans. 67801. The Tieben Pumping Unit is disclosed and claimed in U.S. Pat. No. 4,762,473 issued Aug. 9, 1988. The Tieben Pumping Unit may be mounted directly on the tubing pumping tee with the hydraulic cylinder shaft connected directly to the rod string which drives the downhole pump. The Tieben Pumping Unit may be mounter with a conventional stuffing box and blowout preventer or directly mounted eliminating the stuffing box. The direct mount arrangement results in the pump barrel seals serving the stuffing box function. With such a direct mount arrangement, when the hydraulic cylinder is serviced to change out the seals it is necessary to shut in the well and support the rod string during the servicing.